1. Field of the Invention
The present invention relates to antennas, and more particularly pertains to antennas adapted for use in radio and T.V. application for sending or receiving signals on a plurality of different frequencies.
2. Description of the Prior Art
Prior art antennas known as Sleeve Dipole and Open-Sleeve Dipole utilize coupling between nearby parallel conductors to achieve a non-reactive feedpoint at a second frequency. Those conventional types of antennas are substantially different from antennas pursuant to the present invention. The Sleeve Dipole antenna requires a tubular conductor surrounding a fed dipole or monopole, while the Open-Sleeve Dipole replaces that tubular conductor with two conductors placed on either side of the fed dipole. In known applications, both Sleeve Dipole and Open-Sleeve Dipole antennas operate on two frequencies, the second frequency being a multiple of two of the first frequency. Antennas pursuant to the present invention can be used to obtain operation on two, three, four and more arbitrary frequencies, rather than a specific 2:1 ratio, using only a single additional conductor for each additional frequency.